CA3208683A1

CA3208683A1 - Use of silica nanoparticles with triazine for h2s scavenging

Info

Publication number: CA3208683A1
Application number: CA3208683A
Authority: CA
Inventors: Samuel James Maguire-Boyle; John Edmond Southwell
Original assignee: Nissan Chemical America Inc
Current assignee: Nissan Chemical America Inc
Priority date: 2021-02-19
Filing date: 2022-02-18
Publication date: 2022-08-25
Also published as: WO2022178232A1; JP2024510105A; US20240139680A1; MX2023009601A; AU2022224037A1

Abstract

A process to remove H2S from a stream comprising the steps of adding a silica nanoparticle composition and optionally a triazine, wherein the stream is selected from the group consisting of Oil streams, Gas streams, CO2 point source purification streams and Geothermal Energy System streams.

Description

2 FIELD OF THE INVENTION
This invention is in the field of chemicals used to remove hydrogen sulfide (H2S) from Oil streams, Gas streams, Ca2 point source purification and Geothermal Energy Systems.
B.ACKGROUND OF THE INVENTION
Hydrogen sulfide is present in natural gas from many gas fields. it can also be present in Oil streams, Gas streams, CO2 point source purification and Geothermal Energy Systems.
It is a highly undesirable constituent because it is toxic and corrosive and has a very foul odor. Therefore, several methods for its removal have been developed.
One such method is the injection of an aqueous solution of 1.,3,5-tris(2-irydroxyethyl)hexab ydro-s-triazine lino the gas stream. Triazine is a liquid scavenger so the process is economical up to approximately 50 kg of WS/day and will remove 1425 down to ca. 5 ppm in streams with relatively low concentrations of 1425. However, because the products and the details of the reaction are not known, the optimal conditions for the HIS
removal cannot always be applied. "Hydrolysis of 1,3,5-Ttis(2-hydroxyethyphexahydro-s-triazine and Its Reaction with 1125, Ind,. Eng. Chem. Res. 2.001, 40, 6051-6054, page 6051.
See:
https://www.cotrosionpedia.,cornIdefinition11645/hydrogen- SU] fide-sca.venger-b2s-scavengctr A hydrogen sulfide (142S) scavenger is a specialized chemical or fuel additive widely used in hydrocarbon and chemical processing facilities. These specialized chemicals react selectively with and remove H 25 to help meet product and process specifications.
Products treated for H2S include crude oil, fuels, and other refined petroleum products in storage tanks, tanker ships, railcars, and pipelines.
Hydrogen sulfide can cause damage to pipework, either by reacting directly with stecJ to create an. iron sulfide corrosion film, or by increasing the acidity of the liquid/gas mixture in the pipes. When. dissolved in water, H2S may be oxidized to form elemental sulfur.
17his can also produce an iron sulfide corrosion film when in direct contact with the metal surface. Therefore, it is essential to remove 1-125 from crude oil as quickly and efficiently as possible.
Triazine, the most commonly used liquid WS scavenger, is a heterocyclic structure similar to cyclohexane, but with three carbon atoms replaced by nitrogen atoms. Oilfield terminology of triazine differs from the iLlPAC convention, triazinane.

Three variations of triazine exist, based on the location of the substitution of nitrogen atoms, arc 1,2,3- triazinc; 1,2,4-triazinc and 1,3,5-triazinc (aka s-tria.zine).
Further variations involving substitutions of the hydrogen atoms with other functional groups are used in various industries. The substitutions occurring at any number of the "R" locations, 1,2,3,4,5,or 6. :Different substitutions result in different reactivity with H2S, changes in solubility of triazine, and changes in the solubility of the reactant products (the "R" groups). Consequently, triazine can be "tailored" to better suit the application or disposal considerations.
Direct injection In direct-injection applications, the triazine i.s sprayed directly into the gas or mixed fluid stream, usually with an atomizing quill. Removal rate is dependent upon the H2S dissolution into the triazine solution, rather than the reaction rate.
As a result, gas flow rate, contact time, and misting size & distribution contribute to the final scavenger performance. This method is excellent for removing H2S when there is good annular-mist flow and sufficient time to react. Most suppliers recommend a minimum of 15 -- 20 seconds of contact time with the product for best results.
Typical efficiencies are lower due to the H2S dissolution into the product, but ¨40%
removal efficiency can reasonably be expected. in order for direct injection to be effective, careful consideration of injection location and product selection must be used.
In a contactor tower, the feed gas is bubbled through a tower filled with triazine. As the gas bubbles up through the liquid, gas dissolves into the triazine and.
l-12S is removed. The limiting factors in this application are the surface area of the bubble, the concentration of the solution, and bubble -path time (contact time). Finer bubbles give a better reaction rate, but they can produce unwanted roaming.
This application is not appropriate for high gas flow rates_ Contactor towers have much greater f12S removal efficiencies, up to 80%. As a result, far less chemical is used and a significant reduction in operating expenditures ("OPEX") can be realized_ However, the contactor tower and chemical storage take up significant space and weight, making them less practical for offshore application_ One mole of triazine reacts with two moles of HS to form dithiazine, the main byproduct. An intermediate product is formed, but rarely seen, The R-groups that are released during the two-step reaction vary by the supplier and can be tailored for solubility. Continued reaction, can result in the formation of an insoluble trithiane product.
Reacted triazine byproducts are readily biodegradable and relatively non-toxic.
Unreacted, excess triazine has extremely high aquatic toxicity and a tendency to form carbonate scale with produced water or sea water; this can result in emulsion stabili4ation and increased overboard oil-in-water (01W) content.
Unreacted triazine is also problematic for refineries as it impacts the desalting process and can cause accelerated corrosion within crude oil distillation units. It can also cause foaming in glycol and amine units and cause discoloration of glycol units.
Unpleasant odor has also been reported with excess triazine usage, but some suppliers offer low-odor versions. Triazine itself is relatively safe to handle, but it can cause chemical burns upon contact.
Triazine and derivatives have been used successfully around the globe by many operators and facilities_ it has been used in various other applications where control of low-concentration I-1-.2S is vital, including scale remediation and reservoir stimulation. it is commonly used with sour shale gas production in the US.
Triazine and derivatives are primarily used for removing low (<1M pounds per million standard cubic feet aka "ppinvfmmscf") levels of liHS. These can be applied using a contact tower to increase (up to twice) the efficiency of FI2S
removal, but H,S
levels >200 ppmv/mmscf will require the use of an amine-based sweetening unit.

Triazine is also preferred in situations where the acid gas stream contains high levels of CO2 in addition to II2S. Tue triazine reacts preferentially with the 112S
and the reaction is not inhibited by the CO2, avoiding unnecessary chemical consumption. it is also preferred where a concentrated sour waste gas streams cannot be accommodated or disposed.
US 2018/291284 Al"Microparticles For Capturing Mercaptans" published on October 11,2018 and is assigned to Ecolab. This now abandoned patent application describes and claims scavenging and antifouling nanopartiele compositions useful in applications

3 relating to the production, transportation, storage, and separation of crude oil and natural gas, as well as oral hygiene. Also disclosed are methods of making the natiopartiele compositions a.s scavengers and antifoulants, particularly in applications relating to the production, transportation, storage, and separation of crude oil and natural gas, as well as oral hygiene.
Faeze Tan i Et. Al., "Modified and Systematic Synthesis of Zinc Oxide-Silica Composite Nanoparticles with Optimum Surface Area as a Proper H2S Sorbent", Canadian Journal of Chemical Engineering, vol. 95, No. 4, 1 April 2017, pages 743, describes work done to synthesize high surface area zinc oxide/silica composite nanoparticles via a facile and systemic process. Regarding the importance of surface area in application of such nanoparticles, variation of this factor was studied by change of reaction parameters including concentration of zinc acetate solution, pH, and calcination temperature via Response Surface method combined with Central Composite Design (RSM-CCD). ... Comparison of two 0.1 g/g (lOwt %) ZnO/Silica samples with the optimum (337 m2g-1) and non-optimum (95 m2g-I) surface areas indicated that nanoparticles prepared at the optimum conditions with average diameter of about 18 nm showed a MS adsorption capacity of about 13 mg per gram of sorbent.
US 5980845 "Regeneration of Hydrogen Sulfide Scavengers", issued on Nov. 9, 1999.
This issued US patent describes and claims sulfide scavenger solutions and processes that have high sulfide scavenging capacity, provide a reduction or elimination of solids formation and avoid the use of chemicals that pose environmental concerns. The invention utilizes a dialdehyde, preferably ethanedial, for the purpose of reacting with amines, amine carbonates, or other derivatives of amines that are liberated when certain scavenger solutions react with sulfides, including hydrogen sulfide and mercaptans. The scavenger solutions that have been discovered to liberate amines are those formed by a reaction between an amine and an aldehyde.

4 US 2013/004393 "Synergistic Method for Enhanced H25/Mercaptan Scavenging", issued as US Patent No. 9,463,989 B2 on Oct. 11, 2016. This patent describes and claims the use of a dialdehyde (e.g. glyoxal) and a nitrogen-containing scavenger (e.g. a triazine) when injected separately in media containing hydrogen sulfide (H25) and/or mercaptans to scavenge H2S and/or mercaptans therefrom gives a synergistically better reaction rate and overall scavenging efficiency, i.e. capacity, over the use of the dialdehyde or the nitrogen-containing scavenger used alone, but in the same total amount of the dialdehyde and nitrogen-containing scavenger. The media may include an aqueous phase, a gas phase, a hydrocarbon phase and mixtures of a gas and/or hydrocarbon phase with an aqueous phase.
US 2009/065445 Al, "Aromatic Imine Compounds for use as Sulfide Scavengers", issued as US Patent No. 7,985,881 B2 on July 26, 2011. This patent describes and claims compositions and methods relating to aromatic imine compounds and methods of their use. The compounds are formed from aromatic aldehydes and amino or amino derivatives.
The compounds and their derivatives are useful, for example, as hydrogen sulfide and mercaptan scavengers for use in both water and petroleum products.
US 2018/345212, "Architectured Materials as Additives to Reduce or Inhibit Solid Formation and Scale Deposition and Improve Hydrogen Sulfide Scavenging"
published on Dec.
6, 2018. This patent application describes and claims methods for scavenging hydrogen sulfides from hydrocarbon or aqueous streams and/or reducing or inhibiting solids or scale formation comprising introducing an additive made up of arthitectured materials such as star polymers, hy'uerbranched polymers, and dendrimers that may be used alone or in conjunction with aldehyde-based, triazine-based and/or metal-based hydrogen sulfide scavengers to an aqueous or hydrocarbon stream. A treated fluid comprising a fluid containing hydrogen sulfide and an additive for scavenging hydrogen sulfide or reducing or inhibiting solids and scale formation made up of architectured materials such as star polymers, hyperbranched polymers, and dendrimers. The fluid may further include aldehyde-based, triazine-based and/or metal-based hydrogen sulfide scavengers.

L. Chu et al, "Glycidoxypropyltrimethoxysilane Modified Colloidal Silica Coatings", published in Mat. Res. Soc. Symp. Proc. Vol 435, 0 Materials Research Society, describes the preparation of coatings from a suspension of colloidal silica particles containing glycidoxypropyltrimethoxysilane (GPS) and a polyamine curing agent. GPS was first added to an aqueous silica suspension which contained ethanol (30 wt%) to enhance mxing. The addition of GPS to a basic silica suspension favored condensation among the silane monomers and oligomers, resulting in precipitation.
By contrast, acidic conditions resulted in slower condensation which adsorption of the silane on silica, as followed by ATR-FTIR. After GPS addition and aging, the pH
of the suspension was increased, a polyamine was added and coatings were prepared on polyester web. Coatings with GPS modification were denser, adhered better to the polymer substrate, and could be made thicker than unmodified silica coatings.
"Surface Chemical and hermodynamic Properties of Tglycidoxy-propyltrimethoxysilane-treated alumina: an XPS and IGC study", Chehimi et al, J.
Mat. Chem., 2001, 11, 533-543, The Royal Society of Chemistry 200, describes Alumina and hydrated alumina were treated with hydrolysed T-glycidoxypropyltrimethoxysilane (GPS) in aqueous solution. The powder was then dried at various temperatures ranging from room temperature to 120 C.It was found that the hydration treatment used to create hydroxyl stes was efficient in terms of GPS adsorption. The uptake of GPS was determined by quantitative XPS analysis and the hydrated powders exhibited the highest uptake for all drying temperatures except room temperatures.

SUMMARY OF THE INVENTION
The first aspect of the instant claimed invention is a process to remove I-1.2S
from a stream comprising the steps of adding a) One or more aqueous acidic silica nanoparticle compositions and b) One or more Triazine compounds.
wherein the stream is selected from the group consisting of Oil streams, Gas streams, CO2 point source purification streams and Geothermal Energy System streams.
The second aspect of the instant claimed invention is the process of the first aspect of the invention in which one of the tria.zines present is hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine.
DETAILED DESCRIPTION OF THE INVENTION
For purposes of this patent application, silica nanoparticles include silica nanoparticles, alumina nanoparticles and silica-alumina nanoparticles.
The silica nanoparticles are sourced from all forms of precipitated SiO2 a) dry silica;
b) fumed silica;
c) colloidal silica;
d) surface treated silicas including silicas reacted with organosilanes;
e) metal or metal-oxide with silica combinations; and 0 precipitated silica.
There are known ways to modify the surface of colloidal silica:
1. Covalent attachment of Inorganic oxides other than silica.
2. Non-covalent attachment of small molecule, oligomeric, or polymeric organic materials (PEG treatment, amines or polyamines, sulfides, etc.).
3. Covalent attachment of organic molecule including oligomeric and polymeric species:
a. Reaction with organosilaneskitanates/zirconates/germinates.
b. Formation of organosilanes/titanate/zirconate/germinate oligomers followed by reaction of these with surface of colloidal silica.

c. Silanization followed by post-reaction formation of oligomeric/dendritic/hyperbranched/polymeric species starting from colloidal silica surface.
d. Formation of oligomeric/dendritic/hyperbranched/polymeric silanes/zirconates/titanates followed by reaction to SiO2 surface.
The silica particles included in the colloidal silica may have any suitable average diameter. As used herein, the average diameter of silica particles refers to the average largest cross-sectional dimension of the silica particle. In an embodiment, the silica particles may have an average diameter of between about 0.1 nm and about 100 nm. In an embodiment, the silica particles may have an average diameter of between about 1 nm and about 100 nm.
In an embodiment, the silica particles may have an average diameter of between about

5 nm and about 100 nm. In an embodiment, the silica particles may have an average diameter of between about 1 nm and about 50 nm. In an embodiment, the silica particles may have an average diameter of between about 5 nm and about 50 nm. In an embodiment, the silica particles may have an average diameter of between about 1 nm and about 40 nm. In an embodiment, the silica particles may have an average diameter of between about 5 nm and about 40 nm. In an embodiment, the silica particles may have an average diameter of between about 1 nm and about 30 nm. In an embodiment, the silica particles may have an average diameter of between about 5 nm and about 30 nm. In an embodiment, the silica particles may have an average diameter of between about 7 nm and about 20 nm.
In an embodiment, the silica particles have an average diameter of less than or equal to about 30 nm. In another embodiment, the silica particles may have an average diameter of less than or equal to about 25 nm. In another embodiment, the silica particles may have an average diameter of less than or equal to about 20 nm. In another embodiment, the silica particles may have an average diameter of less than or equal to about 15 nm. In another embodiment, the silica particles may have an average diameter of less than or equal to about 10 nm.
In another embodiment, the silica particles may have an average diameter of less than or equal to about 7 nm. In another embodiment, the silica particles may have an average diameter of at least about 5 nm. In another embodiment, the silica particles may have an average diameter of at least about 7 nm. In another embodiment, the silica particles may have an average diameter of at least about nm. In another embodiment, the silica particles may have an average diameter of at least about 15 nm. In another embodiment, the silica particles may have an average diameter of at least about 20 nm. In another embodiment, the silica particles may have an average diameter of at least about 25 nm. Combinations of the above-referenced ranges are also possible.
Colloidal silica is a flexible technology medium, allowing for customized surface treatment based on application. In an embodiment, the silica is a GlycidoxyPropylTriMethoxySilane-functional silica. GPTMS-functionalized silica includes alkaline sol silica, available from Nissan Chemical America as ST-V3. Another GPTMS-functionalized silica is an acidic type of silica sol, available from Nissan Chemical America as ST-0V3.
The amount of silica nanoparticle used per unit of H2S is as follows:
In an embodiment, 1 unit of silica nanoparticle per 3 units of H2S, in another embodiment, 1 unit of silica nanoparticle per 5 units of H2S and in another embodiment, 1 unit of silica nanoparticle per 10 units of H2S.
The alumina nanoparticles are sourced from all forms of precipitated A1203 a) dry alumina;
b) fumed alumina;
c) colloidal alumina;
d) surface treated aluminas including aluminas reacted with organosilanes;
e) metal or metal-oxide with alumina combinations; and f) precipitated alumina.
There are known ways to modify the surface of colloidal alumina:
1. Covalent attachment of Inorganic oxides other than alumina.
2.
Non-covalent attachment of small molecule, oligomeric, or polymeric organic materials (PEG treatment, amines or polyamines, sulfides, etc.).
3. Covalent attachment of organic molecule including oligomeric and polymeric species:
a. Reaction with organosilanes/titanates/zirconates/germinates.
b. Formation of organosilanes/titanate/zirconate/germinate oligomers followed by reaction of these with surface of colloidal alumina.
c. Silanization followed by post-reaction formation of oligomeric/dendritic/hyperbranched/polymeric species starting from colloidal alumina surface.

d. Formation of oligomeric/dendritic/hyperbranched/polymeric silanes/zirconates/titanates followed by reaction to A1203 surface.
The alumina particles included in the colloidal alumina may have any suitable average diameter. As used herein, the average diameter of alumina particles refers to the average largest cross-sectional dimension of the alumina particle. In an embodiment, the alumina particles may have an average diameter of between about 0.1 nm and about 100 nm. In another embodiment, the alumina particles may have an average diameter of between about 1 nm and about 100 nm.
In another embodiment, the alumina particles may have an average diameter of between about 5 nm and about 100 nm. In another embodiment, the alumina particles may have an average diameter of between about 1 nm and about 50 nm. In another embodiment, the alumina particles may have an average diameter of between about 5 nm and about 50 nm. In another embodiment, the alumina particles may have an average diameter of between about 1 nm and about 40 nm. In another embodiment, the alumina particles may have an average diameter of between about 5 nm and about 40 nm. In another embodiment, the alumina particles may have an average diameter of between about 1 nm and about 30 nm. In another embodiment, the alumina particles may have an average diameter of between about 5 nm and about 30 nm. In another embodiment, the alumina particles may have an average diameter of between about 7 nm and about 20 nm.
In an embodiment, the alumina particles have an average diameter of less than or equal to about 30 nm. In an embodiment, the alumina particles have an average diameter of less than or equal to about 25 nm. In an embodiment, the alumina particles have an average diameter of less than or equal to about 20 nm. In an embodiment, the alumina particles have an average diameter of less than or equal to about 15 nm. In an embodiment, the alumina particles have an average diameter of less than or equal to about 10 nm. In an embodiment, the alumina particles have an average diameter of less than or equal to about 7 nm. In an embodiment, the alumina particles have an average diameter of at least about 5 nm. In an embodiment, the alumina particles have an average diameter of at least about 7 nm. In an embodiment, the alumina particles have an average diameter of at least about 10 nm. In an embodiment, the alumina particles have an average diameter of at least about 15 nm. In an embodiment, the alumina particles have an average diameter of at least about 20 nm. In an embodiment, the alumina particles have an average diameter of at least about 25 nm. Combinations of the above-referenced ranges arc also possible.
Colloidal alumina is a flexible technology medium, allowing for customized surface treatment based on application. In an embodiment, the alumina is a GPTMS-functional alumina. GlycidoxyPropylTriMethoxySilane-functional alumina includes alkaline sol silica, available from Nissan Chemical America as AT-V6. Another GPTMS-functionalized alumina is an acidic type of silica sol, available from Nissan Chemical America as AT-0V6.
The amount of alumina nanoparticle used per unit of H2S is as follows:
1 unit of alumina nanoparticle per 3 units of H2S, in another embodiment, 1 unit of alumina nanoparticle per 5 units of H2S and in another embodiment, 1 unit of alumina nanoparticle per units of H2S.
Some examples of nanoparticles can include particles of spherical shape, fused particles such as fused silica or alumina or particles grown in an autoclave to form a raspberry style morphology, or elongated silica particles. The particles being bare, or surface treated. When surface treated may be polar or non-polar The surface treatment is sufficient to allow the nanoparticle to be stable during transportation to the area where a I-12S sorbent is required and for delivery.
The stability achieved either by covalent, charge-charge, dipole-dipole, or charge-dipole interactions.
Triazines useful in the instant claimed invention include, but are not limited to, 1,2,3- triazine; 1,2,4-triazine and 1,3,54riazine (aka s-tria zinc).
Triazines useful in the instant claimed invention include Hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine.
Triazines are alkaline and can cause carbonate scaling. Triazines are commercially available.
Triazines can be present in the process at a level of from about zero point I
(0.1) units to a.bout 1 unit per 3 units of I-12S. Units could mean any quantitative measure, such as grams, pounds, mols, etc. etc.

CO2 Point Source Purification is described in "Evaluation of CO2 Purification Requirements and the Selection of Processes for Impurities Deep Removal from the CO, Product Stream", Zeina Abbas et al, Energy Procedia, Volume 37, 2013, Pages 2389-2396.
Depending on the reference power plant, the type of fuel and the capture method used, the CO, product stream contains several impurities which may have a negative impact on pipeline transportation, geological storage and/or Enhanced Oil Recovery (EOR) applications. All negative impacts require setting stringent quality standards for each application and purifying the CO2. stream prior to exposing it to any of these applications.
In the Abbas paper, the CO2 stream specifications and impurities from the conventional post-combustion capture technology are assessed. Furthermore, the CO2 restricted purification requirements for pipeline transportation, FOR and geological storage are evaluated. Upon the comparison of the levels of impurities present in the CO2 stream and their restricted targets, it was found that the two major impurities which entail deep removal, due to operational concerns, are oxygen and water from 300 ppmv to 1_0 ppmv and 7.3% to 50 ppmv respectively. Moreover, a list of plausible tc.chnologies for oxygen and water removal is explored after which the selection of the most promising technologies is made. It wa.s found that catalytic oxidation of hydrogen and refrigeration and condensation are the most promising technologies for oxygen and water removal respectively.
"Geothermal Energy System Streams" are described as follows:
* Hot water is pumped from deep underground through a well under high pressure.
= When the water reaches the surface, the pressure is dropped, which causes the water to turn into steam.
= The steam spins a turbine, which is connected to a generator that produces electricity.
= The steam cools off in a cooling tower and condenses back to water.
Examples Materials:
Stepanquat 200 is a 78.5% actives solution of Hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine available commercially from Stepan Corp.

ST-040, ST-30, ST-0V4, PGM-ST, ST-C, ST-V3, and MT-ST are commercially available colloidal silica products from Nissan Chemical America Corporation.
Organosilanes, Propylene Glycol Monomethyl Ether solvent, NaHCO3. CuC12-H20, and Glyoxal were procured from Sigma Aldrich Corp.
Synthesis example 1: 1000mL Snowtex0 ST-30 from Nissan Chemical America Corporation (Aqueous alkaline colloidal silica dispersion, 30wt% SiO2 solids, 10-15 median particle size) was placed into a 2000mL 4 neck glass reactor assembled with addition funnel, thermometer, heating mantle connected to voltage regulator, and mixer with 2 inch diameter trifoil mixing blade. Mixing was activated at 150rpm and silicasol was brought to 50 C. Into the addition funnel was weighed 49.98g of Aminoethylaminoethylaminopropyl Trimethoxysilane (CAS#
35141-30-1, Sigma-Aldrich). Addition funnel was assembled to reactor top and silane was slowly added to stirring silicasol at a drop rate of 2 drops per second. After all organosilane had been added to reaction the mixture was allowed to stir at 50 C for a period of 3 hours. Finished surface-treated alkaline silica was poured off to a 2L Nalgene bottle for storage and use.
Synthesis Example 2:
1.4L Snowtexe 0-XS (Aqueous acidic colloidal silica dispersion, lOwt%
colloidal silica median particle size 5nm) was transferred to a 4-neck reaction kettle. To this vessel were also added 9.6L
distilled water. Copper (II) Chloride dehydrate (CuC12-H20, Sigma Aldrich), 13.87g were added to the reaction flask and allowed to dissolve at room temperature under light agitation. A stock solution (-Solution A") of NaHCO3 (Sigma Aldrich ACS reagent grade, >99.7% was prepared (47.04g NaHCO1 dissolved in 12.6L distilled water, 0.04 M final concentration). The stir rate in the reaction vessel was increased to 9500rpm to achieve vigorous agitation.
Solution A was added slowly 10-15mL per minute to the reaction via addition funnel. After Solution A was added completely the reaction was allowed to stir at room temperature for 30 minutes and contents were removed for storage and use.
Synthesis Example 3:
Snowtex0 PGM-ST (Solvent borne dispersion of acidic colloidal silica, 30wt%
SiO2 median particle size 10-15nm dispersed in Propylene Glycol Monomethyl ether). 450g were placed into a 1000mL 4-neck reaction flask. Similar to Synthesis Example 1 the reactor was assembled with mixer, thermometer, and heating mantle/voltage regulator. A 4.05g portion of 3-Mercaptopropyl Trimethoxysilane (Sigma Aldrich) were added to an addition funnel and assembled to the reactor. PGM-ST was brought to 50 C under mild agitation and Mercaptopropyl trimethoxysilane was added dropwise via addition funnel at 1 drop/second until addition was complete. Reaction was kept at 50 C for a period of 3 hours, then the surface-treated silicasol was poured off to a Nalgene container for storage and use.
Example 1, Comparative:
Into a 1000mL Nalgene bottle were placed 300g distilled H20. 300g Propylene Glycol Monomethyl Ether ("PGM") solvent, and 300g Stepanquat 200. Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 2:
Into a 1000mL Nalgene bottle were placed 300g distilled H20. 300g Propylene Glycol Monomethyl Ether solvent, and 300g Synthesis Example 1 fluid. Contents were mixed thoroughly by shaking container vigorously for 30 seconds.

Example 3, Comparative:
Into a 1000mL Nalgene bottle were placed 700g distilled H20. and 300g Stepanquat 200.
Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 4:
Into a 1000mL Nalgene bottle were placed 300g distilled H20. 300g ST-040 (Aqueous acidic colloidal silica available from Nissan Chemical America Corporation) , and 300g Stepanquat 200. Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 5:
Into a 1000mL Nalgene bottle were placed 300g distilled H20. 300g Synthesis Example 2 fluid, and 300g Stepanquat 200. Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 6:
Into a 1000mL Nalgene bottle were placed 300g distilled H20. 300g ST-0V4 (Aqueous acidic hydrophilic surface treated colloidal silica available from Nissan Chemical America Corporation) , and 300 g Stepanquat 200. Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 7:
Into a 1000mL Nalgene bottle were placed 300g distilled H20, 300g Synthesis Example 3 fluid, and 300g Stepanquat 200. Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 8:
Into a 1000mL Nalgene bottle were placed 375g aqueous solution of Glyoxal (Sigma Aldrich, 37.5 wt%) and 625g ST-C (Aqueous alkaline colloidal silica dispersion partially surface treated with Aluminum Oxide available from Nissan Chemical America Corporation) .
Contents were mixed thoroughly by shaking container vigorously for 30 seconds.

Example 9:
Into a 1000mL Nalgene bottle were placed 375g aqueous solution of Glyoxal (Sigma Aldrich, 37.5 wt%) and 625g ST-040 (Aqueous acidic colloidal silica dispersion available from Nissan Chemical America Corporation) . Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 10:
Into a 1000mL Nalgene bottle were placed 375g aqueous solution of Glyoxal (Sigma Aldrich, 37.5 wt%) and 625g ST-V3 (Aqueous alkaline hydrophilic surface treated colloidal silica dispersion available from Nissan Chemical America Corporation) . Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 11:
Into a 1000mL Nalgene bottle were placed 375g aqueous solution of Glyoxal (Sigma Aldrich, 37.5 wt%) and 625g MT-ST (Solvent borne acidic colloidal silica dispersed in Methanol, 30wt%
SiO2, 10-15nm median particle size, available from Nissan Chemical America Corporation).
Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
Example 12: Comparative Into a 1000mL Nalgene bottle were placed 375g aqueous solution of Glyoxal (Sigma Aldrich, 37.5 wt%) and 625g distilled H20. Contents were mixed thoroughly by shaking container vigorously for 30 seconds.
MEA Triazine was kept at a constant concentration across all the Inventive and Comparative examples. Similarly, Glyoxal concentration was kept constant across all Inventive and Comparative examples.
Testing for removal of H2S
Each solution tested was equilibrated for weight at 300g total solution and placed into a vessel with overhead port to measure H2S content in the vessel headspace. The headspace port was connected to a Drager Pac 3500 gas monitor (Dragerwerk AG&Co. KGaA). A mixed gas of 10%H1S/90% Nitrogen was bubbled through the test solution at a standard rate of 475mL/minute, solution held at 22 C, and headspace monitored for H2S content.
A reading of 0 means the sensor is not detecting any H2S in the flow gas stream after the gas has passed through the tested solution. Vessel headspace was monitored for H2S content once per minute continuously until a H2S content of 40 reading on gas monitor was reached, at which point the test example in solution reacting with H2S was considered to be consumed and the experiment stopped. Times to initial H2S reading and Time to complete H2S breakthrough were recorded and compared to controls/comparative examples.

Summary of Results The Number of minutes is listed is how long the detector detected a value of "0" for H2S. The Table is ordered from best performance in terms of removal of H2S to worst performance.
Time to Time to initial H2S 40% H2S
reading reading Example (minutes) (minutes) Composition nanoparticle type_ Triazine+Water+ Amine Amine-Functional 2 124 160 func. SiO2 SiO2 1: ri az i tie+ W tter+ PG M solvent 1 117 145 (Comparative Exam plek none Aluminum oxide 8 107 184 Glyoxal+ ST-C functional SiO2 Aqueous acidic 4 71 164 Triazine+Water+ ST-040 SiO2 Glycidoxy functional SiO2, 10 55 146 Glyoxal+ ST-V3 alkaline Transition Metal 5 55 139 Triazine+Water+ CuOXS
functional SiO2 Triazine+Water+ Mercapto Mercapto 7 55 105 functionalized PGM-ST
Functional SiO2 Aqueous acidic 9 51 86 4 Glyoxal+ ST-040 SiO2 Ti i iiiie + N7Vitet- ([7 omparative 3 44 61 Exaniple):: none Glycidoxy functional SiO2,

6 39 153 Triazine+Water+ST-0V4 acidic Glyoxal+Water (Comparative none Solventborne 11 1 2 Glyoxal+ MT-ST SiO2, acidic Observations about the Examples:
1. Example 1: This is a Triazine controls/comparative examples with MEA
Triazine dissolved in a mixture of water and PGM solvent. This example performed very well, much better than MEA Triazine alone at the same concentration dissolved in water. It is believed, without intending to be bound there bye, that it is possible PGM is actually very beneficial in Triazine + H2S reaction.
2. Example 2 (Amine-functional SiO2 combined with Triazine) performed very well compared to the comparative example, with improved/delayed time to initial H2S

breakthrough and also time to final breakthrough (when the H2S readings reached a 40%
level in the headspace above the sample).
3. Example 3 is the Triazine + water control, these times were used comparatively for all the Triazine + nanosilica examples. Example 3 exemplifies the standard field grade fluid of MEA Triazine fluid for treatment of sour gas.
4. Example 4 (ST-040, Aqueous acidic silica + Triazine) performed the best of all Triazine + nanosilica examples. It is believed, without intending to be bound thereby, that the solid acidity of the acidic silica surface is likely acting as a catalyst to make the Triazine + H2S reaction more complete, leading to greatly improved/delayed time to initial and complete H2S breakthrough.
5. Example 5 (Copper functionalized nanosilica+ Triazine) performed relatively well in improved/delayed time to initial and complete H2S breakthrough. This example is the only example of Transition Metal functional silica. (It is noted that the Aluminum present in Example 8 is not considered a true Transition metal, as it is a -Post Transition Metal".) 6. Example 6 (ST-0V4 + Triazine) is aqueous acidic silica functionalized with hydrophilic organic surface treatment and is commercially available from Nissan Chemical America. This example had slightly worse time to H2S initial breakthrough, but had a greatly improved time to complete H2S breakthrough compared to the control (Example 3).

7. Example 7 (Mercapto-functional nanosilica dispersed in PGM + Triazine) ¨
Slightly improved time to initial H2S breakthrough and much improved time to complete breakthrough. It is believed, without intending to be bound thereby, that the Mercapto surface functionality can disrupt polymer formation in the Triazinc + H2S
reaction.

8. Example 8 is ST-C (Aqueous alkaline colloidal silica with Aluminum Oxide surface) combined with Glyoxal. Compared to Glyoxal alone this combination of ST-C +
Glyoxal showed dramatic improvements in both time to initial and time to complete H2S
breakthrough. The Glyoxal + nanosilica examples performed relatively well. It is noted that the Aluminum present in Ex. 8 is not considered a true Transition metal, as it is a -Post Transition Metal".

9. Example 9 (ST-040 + Glyoxal) performed much better than Glyoxal alone.

10. Example 10 (ST-V3, Aqueous alkaline silica with hydrophilic organic surface treatment + Glyoxal) performed very well compared to Glyoxal alone.

11. Example 11 (Acidic silica dispersed in Methanol) did not perform well, this example had the worst results of all. It is believed, without intending to be bound thereby that MT-ST
completely deactivated Glyoxal from reacting with H2SJ

12. Example 12 is the solution of Glyoxal and water only, a comparative example with no added nanotechnology.

Claims

1, A process to remove I-12S from a. stream comprising the steps of adding cl One or more aqueous acidic silica. nauoparticle compositions and d) One or more Triazine compounds.
wherein the stream is selected from the group consisting of Oil streams, Gas streams, CO2 point source purification streams and Geothermal Energy System streams.

2. The process of Claim 1 in which one of the triazines present is hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine.

3. The process of Claim 1 in which the strea.m i.s a.n Oil stream.

4. The process of Claim 1 in which the stream is a Gas stream.

5. The process of Claim 1 in which the stream is a CC*, point source purification stream.

6. The process of Claim 1 in which the stream is a Geothermal Energy System stream.